Effects of soil tillage system on yield and weeding level in wheat crop

This paper presents the yield and evolution of weeding level in wheat crop, as part of a three-year soybean-winter wheat-corn rotation, with the implementation of minimum soil tillage variants with: rotary harrow, paraplow and chisel plough. The experiment has been conducted on a Phaeozem argic soil type in Transylvania Plain, with conventional and four minimum tillage systems of soil cultivation. The level of weeding was influenced by the soil tillage system in the phase of springing up to the harvest of the wheat crop. At crop spring­ing, the total number of weeds was 31.8 weeds/m2 in the variant with plough + rotary har­row and between 31.6-34.7 weeds/m2 in minimum tillage variants. A greater number of perennial dicotyledonous weeds can be recorded in the minimum tillage variant (between 1.2-1.6 weeds/m2), when compared with plough + rotary harrow variant (0.9 weeds/m2). At the crop harvest stage, the number of weeds was 8.2-50.6% higher in the variants with minimum tillage system, when compared to the conventional tillage system. A decrease in the percent of annual dicotyledonous weeds is evident, from 85.9% in the variant with plough, to 71.5-78.9% in the variants with minimum tillage systems, with an increase in perennial dicotyledonous (from 7.9% to 8.4-13.8%) and monocotyledonous weeds (from 6.2 to 11.6-20%). The changes in the floristic content of weeding level indicates the need for changing the strategies of weed control in winter wheat crop in the variants with mini­mum soil tillage systems. Increasing the percent of perennial dicotyledonous weeds by 59% (from 7.9% to 13.8%) makes the wheat cultivation in crop rotation with leguminous nec­essary, completed with the use of specific herbicide methods, in previous crop and wheat crop. The presence of monocotyledonous weeds of about 11.6% to 20.0% completes the necessity for the application of different strategies of control and correlation, for the weed­ing level as well as the type of weed, including their annual or perennial character. Yields obtained by applying minimum tillage were 97.8-98.2%, when paraplow and chisel are compared to plough and were significantly lower in the rotary harrow variant, while weed­ing level was the highest.